ETIDRONIC ACID- ▸ Scale inhibition: threshold scale control in water systems
- ▸ Corrosion inhibition: metal-surface protection in cooling water
- ▸ Chelation/sequestration: metal-ion control in detergents and cleaners
- ▸ Stabilizer: peroxide and bleach stabilization
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
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Transport classification per the UN Model Regulations / 49 CFR 172.101 Hazardous Materials Table. Confirm against the grade-specific SDS (Section 14) before shipping.
Hydroxyethylidene diphosphonic acid (HEDP, CAS 2809-21-4) is an organophosphonic-acid chelating agent. It is used as a sequestrant, scale and corrosion inhibitor, and stabilizer in water treatment, detergents, and industrial cleaning.
Frequently Asked Questions
What is hydroxyethylidene diphosphonic acid used for?
HEDP (CAS 2809-21-4) is an organophosphonic-acid chelating agent used as a threshold scale inhibitor and corrosion inhibitor in water systems, as a sequestrant for metal-ion control in detergents and industrial cleaners, and as a peroxide and bleach stabilizer.
What is another name for HEDP?
HEDP is also known as etidronic acid and as 1-hydroxyethylidene-1,1-diphosphonic acid (CAS 2809-21-4). Its molecular formula is C2H8O7P2.
How is HEDP made?
HEDP is an organophosphonic acid produced industrially by reacting acetic acid or acetic anhydride with phosphorus compounds such as phosphorus trichloride to form the geminal diphosphonate. It is supplied as an aqueous solution at standard active concentrations; confirm assay on the CoA.
What concentration and CAS number does HEDP ship at?
HEDP is CAS 2809-21-4 and is commonly supplied as an aqueous solution (for example around 60% active), with solid and partially neutralized salt grades also available. Confirm the active-acid content and grade against the Certificate of Analysis; an SDS ships with each lot.
How is HEDP supplied in bulk?
RawSource supplies HEDP in drums, IBC totes, and larger bulk for water-treatment, detergent, and cleaning formulators. Request a bulk quote for current pricing, active concentration, packaging, and lead time.